Modbus Slave for the Hitachi TM H-252 Series

Transcription

1 User s Manual for the HE150RTU100 Modbus Slave for the Hitachi TM H-252 Series First Edition November 05, 1998 MAN0121(E)-01

2 PAGE 2 5-Nov-1998 PREFACE PREFACE This manual explains how to use the Horner Electric s Modbus (RTU) slave for the Hitachi H-252 Series. Copyright 1998 Horner Electric, Inc., 640 North Sherman Drive Indianapolis, Indiana All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior agreement and written permission of Horner Electric, Inc. All software described in this document or media is also copyrighted material subject to the terms and conditions of the Horner Software License Agreement. Information in this document is subject to change without notice and does not represent a commitment on the part of Horner Electric, Inc. Hitachi is a trademark of Hitachi Corporation. For user manual updates, contact Horner Electric Advanced Products Group, Technical Support Division, at (317) or visit our website at

3 PAGE 3 5-Nov-1998 PREFACE LIMITED WARRANTY AND LIMITATION OF LIABILITY Horner Electric, Inc. ("HE") warrants to the original purchaser that the Modbus Slave manufactured by HE is free from defects in material and workmanship under normal use and service. The obligation of HE under this warranty shall be limited to the repair or exchange of any part or parts which may prove defective under normal use and service within two (2) years from the date of manufacture or eighteen (18) months from the date of installation by the original purchaser whichever occurs first, such defect to be disclosed to the satisfaction of HE after examination by HE of the allegedly defective part or parts. THIS WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR USE AND OF ALL OTHER OBLIGATIONS OR LIABILITIES AND HE NEITHER ASSUMES, NOR AUTHORIZES ANY OTHER PERSON TO ASSUME FOR HE, ANY OTHER LIABILITY IN CONNECTION WITH THE SALE OF THIS Modbus Slave. THIS WARRANTY SHALL NOT APPLY TO THIS MODBUS SLAVE. OR ANY PART THEREOF WHICH HAS BEEN SUBJECT TO ACCIDENT, NEGLIGENCE, ALTERATION, ABUSE, OR MISUSE. HE MAKES NO WARRANTY WHATSOEVER IN RESPECT TO ACCESSORIES OR PARTS NOT SUPPLIED BY HE. THE TERM "ORIGINAL PURCHASER", AS USED IN THIS WARRANTY, SHALL BE DEEMED TO MEAN THAT PERSON FOR WHOM MODBUS SLAVE IS ORIGINALLY INSTALLED. THIS WARRANTY SHALL APPLY ONLY WITHIN THE BOUNDARIES OF THE CONTINENTAL UNITED STATES. In no event, whether as a result of breach of contract, warranty, tort (including negligence) or otherwise, shall HE or its suppliers be liable of any special, consequential, incidental or penal damages including, but not limited to, loss of profit or revenues, loss of use of the products or any associated equipment, damage to associated equipment, cost of capital, cost of substitute products, facilities, services or replacement power, down time costs, or claims of original purchaser's customers for such damages. To obtain warranty service, return the product to your distributor with a description of the problem, proof of purchase, post paid, insured and in a suitable package. ABOUT PROGRAMMING EXAMPLES Any example programs and program segments in this manual or provided on accompanying diskettes are included solely for illustrative purposes. Due to the many variables and requirements associated with any particular installation, Horner Electric cannot assume responsibility or liability for actual use based on the examples and diagrams. It is the sole responsibility of the system designer utilising the Module to appropriately design the end system, to appropriately integrate the Module and to make safety provisions for the end equipment as is usual and customary in industrial applications as defined in any codes or standards which apply. Note: The programming examples shown in this manual are illustrative only. Proper machine operation is the sole responsibility of the system integrator.

4 PAGE 4 5-Nov-1998 PREFACE TABLE OF CONTENTS PREFACE...2 LIMITED WARRANTY AND LIMITATION OF LIABILITY...3 ABOUT PROGRAMMING EXAMPLES...3 TABLE OF CONTENTS...4 CHAPTER 1: INTRODUCITON General Specifications System Requirements Physical Layout Jumper Settings...6 CHAPTER 2: INSTALLATION AND CONFIGURATION Basic Module Installation PLC Configuration for Module Configuration Link Words (WL0000 to WL0005) Configuration Example...9 CHAPTER 3: OPERATION Modbus Protocol Port Selection Frame Protocol Handshaking DCS Active Detection Front Panel Diagnostic LED s Supported Modbus Commands Modbus command descriptions Read Exception Status command (HE150RTU100 specifics) Loopback Diagnostics Test command (HE150RTU100 specifics) Modbus Responses CHAPTER 4: WIRING RS-232 Connections RS-485 Connections...1

5 PAGE 5 5-Nov-1998 CHAPTER 1: INTRODUCTION CHAPTER 1: INTRODUCITON 1.1 General Congratulations on your purchase of the Horner Electric s Modbus Slave for the Hitachi H-252 series. The HE150RTU100 is a Modbus slave module that allows Modbus communications on either RS-232 or RS-485. The HE150RTU100 allows a Modbus master to access H-252 series PLC reference data as though it were Modbus I/O. This data may be accessed using standard Modbus commands such as Read / Force Coils and Read / Preset Registers. The data accessible on the H-252 series PLC is the CPU Link data area. Data in the CPU Link area may be accessed from the PLC by either word or bit accesses. Likewise, when accessing that data though Modbus, an analogue command will reference the associated WL word data and a discrete command will reference the associated L bit data. Read and Write packets of up to 2000 discrete or 125 analogue values are supported. Message reception LED s and Modbus Diagnostic and Exception commands are also supported to provide easy set-up and troubleshooting. Also provided to the PLC is a time-out indicator (DCS active) which indicates a break in communications with the Modbus master. Configuration of the port operation and associated frame protocol parameters are easily accomplished by setting 6 Link words (WL0000 through WL0005) with an arithmetic block in the PLC. Baud rates of up to 115.2K are supported in either ASCII or RTU modes. Note that there are limitations in the number of stop bits and parity selections. 1.2 Specifications Table 1.1 HE150RTU100 Specifications Mounting Requirement One I/O slot in BSH rack Power Requirements 5VDC Operating Environment 0 to 60 o C (32 to 140 o F) 0 to 95% humidity (non-condensing) User Memory Dual-port 1,024 words (2,048 bytes) Communications One RS-232 port One RS-485 port Protocol MODBUS Speed 300 to 115,200 Baud Modes RTU or ASCII 1.3 System Requirements The HE150RTU100 Module requires: a. One I/O slot in a BSH rack (follow directions in the PLC manual for module insertion and removal); b. One H-252, H-252B or H-252C CPU; c. Programming software for the PLC (Actsip-H, ActWin or other). 1.4 Physical Layout Two important precautions should be observed while handling the module: 1. Never insert or remove the module into or out of the PLC unit while power is applied to the backplane. If this practice is repeated, the module WILL eventually BE DAMAGED. 2. Always observe reasonable static discharge precautions while handling the module. Touch a grounded metal surface to discharge any static build-up before touching the module

6 PAGE 6 5-Nov-1998 CHAPTER 1: INTRODUCTION RTU Slave Module DCS JP6 Horner Electric U12 U11 U10 TXA RXA RS-232 Port JP5 JP1 U1 U2 P4 TXB RXB RS-485 Port JP2 JP4 U14 JP3 P5 Figure 1.1 HE150RTU Jumper Settings The HE150RTU100 is equipped with several hardware jumpers. JP1, JP3, JP5 and JP6 are factoryconfigured jumpers. The user should not modify these jumpers! Changing any of the pre-configured jumpers may cause the module to malfunction! Table 1.2 Jumper Setting JP1 Short pins 2 and 3 to enable watchdog (recommended) Short pins 1 and 2 to disable watchdog JP2 Short to apply +5VDC to the RS-485 port JP3 Hitachi module ID code. Short pins 3 and 4 for CPU Link module JP4 NV-RAM density. Short pins 1 and 2 for 64k or 128k; open for 32k. JP5 Short pins 1 and 2 to cause MPU port 1, bit 1 to read back as a 0. JP6 Short pins 1 and 2 to allow the PLC to reset the module by asserting a back-plane reset signal. If open, the module is reset by power cycle or watchdog. JP2 enables and disables the 5 VDC power supply on pin 5 of the 15 pin auxiliary port. If this jumper is installed, 5 VDC is supplied to pin 5. STOP! Do not connect pin 5 of the auxiliary port to pin 5 on the PLC programming port with JP2 installed. If these pins are connected with this jumper installed, DAMAGE WILL BE CAUSED TO BOTH THE PLC POWER SUPPLY AND THE ASCII BASIC MODULE! JP4 sets the RAM density. Short pins 1 and 2 for 64k or 128k; open for 32k. This jumper needs to be changed if additional memory is added.

7 PAGE 7 5-Nov-1998 CHAPTER 2: INSTALL/CONFIG. CHAPTER 2: INSTALLATION AND CONFIGURATION 2.1 Basic Module Installation 1. Remove power to the CPU/Base. 2. Install the HE150RTU100 module in a free slot (see limitations below). 3. Configure the PLC CPU Link Parameter and I/O slot type as Link. 4. Insert a block in the PLC program to initialise the 6 configuration Link words (WL0 to WL5). 5. Connect the Modbus master to the appropriate port. 6. Start Modbus master application. 2.2 PLC Configuration for Module The HE150RTU100 is a CPU Link type module (see Hitachi manuals for more information). Up to twolink type modules can be placed in a higher function base with a CPU module. Do not place the HE150RTU100 in an expansion base. Each installed link type module requires configuration information to be entered into the PLC though a programming device. This information contains the position and type of module in the base, and the link parameter, which defines the output area, used by the HE150RTU100. Two data areas are reserved in the PLC for up to two CPU Link modules. Each area is dedicated to its associated CPU Link module and is 1,024 words wide. Each data area is also dividable (though PLC setup) into an input and output section. The area designated as output is continuously transferred from the PLC to the HE150RTU100. The area designated as input is continuously transferred from the HE150RTU100 to the PLC. Therefore, the PLC program blocks must reference data elements in the area designated as output for sending data to the Master and reference the data elements in the area designated as inputs for receiving data from the Master. Likewise, the Modbus master must use offsets into the output area for reading data and offsets into the output area for writing data. CPU TOP END Remainder INPUT OUTPUT HE150RTU100 Figure 2.1 Hitachi Link Areas The data output area is defined with the programming device under PLC set-up / Link Parameters (1 & 2). Link Parameter 1 is for the leftmost CPU Link module in the base. Link Parameter 2 is for the rightmost additional CPU Link module in the base. Each Link Parameter has two separate values that are Top and End. Setting the Top and End Link Parameters sets the space in the Link data area that is designated output. The remainder of the 1,024 words is designated as input. See below for Link Parameters Top and End limitations. NOTE: With the HE150RTU100 properly inserted and configured, the CPU when going to RUN mode may give a Self-Diagnostic-Error (WRF00) indication of [59] Special-Function-Module-Error. This is not a fatal error and can be ignored. If any other error is specified for the base location of the HE150RTU100, check in the CPU user s manual for more information.

8 PAGE 8 5-Nov-1998 CHAPTER 2: INSTALL/CONFIG. 2.3 Configuration Link Words (WL0000 to WL0005) When configuring the PLC, the Link Parameters entry for the associated HE150RTU100 must start at WL0000 (Top) and end at or above WL0005 (End). This 6-word area must be updated by the PLC with the port configuration parameters for the HE150RTU100. If additional write area is for the CPU, link area is continued immediately above the configuration link words by extending the End parameter. Furthermore, use care not to overwrite the configuration link words during operation. The HE150RTU100 continuously monitors WL0000 to WL0005 for the initial configuration and any changes thereafter. The HE150RTU100 reconfigures the Modbus port any time the Valid-configurationpresent-identifier word (WL0005) changes from a value not equal to A5A5H to a value equal to A5A5H. Note: At start-up and when the identifier word is not equal to A5A5H the DCS light remains lit solid to indicate that the HE150RTU100 is not configured. Additionally, if the port was previously configured and the identifier word is changed from A5A5H, Modbus requests will return a Device Error. The following specifies the format of the Configuration Link words: Table 2.1 Configuration Link Words Link Word Description Options WL0000 Slave Station ID 1 to 247 WL0001 Port Parameter See Table 2.2 WL0002 Radio Modem Turn-Around-Time (ms) 0 to disable; 1 to 1000 WL0003 DCS Time-out (seconds) 0 to disable; 1 to 320 WL0004 DCS Status Bit (set if loss of Any Link bit above END (i.e., L1000) communication with Master) WL0005 Valid configuration present identifier A5A5H for valid configuration Anything else for invalid configuration Table 2.2 Configuration Link Word WL0001 Link Bit Description Options 0010 Stop Bits 0=1 Stop Bit, 1=2 Stop Bits 0011 Use Parity Bit 0=No Parity Bit, 1=Parity Bit 0012 Type of Parity 0=Odd Parity, 1=Even Parity 0013 Port 0=RS-232, 1=RS Modbus Transfer mode 0=ASCII Mode, 1=RTU Mode 0015 Not Used Not Used Not Used =None, 1=Software, 2=Hardware, Port Handshaking =Multi-drop, 4=Radio Modem 001A Not Used 0 001B Not Used 0 001C 001D 001E 001F Port Baud Rate 0 = = = 28,800 1 = = = 38,400 2 = = 14,400 A = 57,600 3 = = 19,200 B = 115,200

9 PAGE 9 5-Nov-1998 CHAPTER 2: INSTALL/CONFIG. 2.5 Configuration Example The following configuration sets up the HE150RTU100 at slave station ID 12. The protocol properties are RS-232, 9600 baud, 2 stop bits, no parity and no handshaking. The modem TAT is disabled. DCS is enabled with a delay of 60s and L1000 is used as the DCS Status Bit. The CPU write-space is set to WL0000 to WL00FF. The HE150RTU100 is placed in slot 3 and can write from WL0100 to WL03FF. Table 2.3 Configuration Example Setting Link Word Value Slave Station ID = 12 WL or 000AH Port Parameter 2 Stop Bits No Parity RS-232 Port RTU Mode WL or 5011H No Handshaking 9600 Baud Radio Modem Turn-Around-Time = Disabled WL DCS Time-out = 60 seconds WL or 3CH DCS Status Bit use L1000 WL or 1000H Valid configuration present identifier WL or A5A5H CPU Settings WL1 TOP 0000 END 00FF Setting WL0000 to WL0005 is generally accomplished using an arithmetic block as shown in Figure 2.2. WL0000 = 12 WL0001 = WL0002 = 0 WL0003 = 60 WL0004 = 4096 WL0005 = Figure 2.2 Arithmetic Block Example Note: WL0005 must be set not equal to A5A5H and then equal to A5A5H any time the configuration is changes for the new configuration to take effect.

10 PAGE 10 5-Nov-1998 CHAPTER 3: OPERATION CHAPTER 3: OPERATION 3.1 Modbus Protocol Modbus is a master/slave protocol that supports on a common bus one master and up to 247 slaves. Note that when RS-485 is used for Modbus, it is typically limited to 32 units. As a Modbus slave, the HE150RTU100, must be assigned a unique address. Address 0 is reserved for broadcasting a message to all nodes. The HE150RTU100 processes broadcast messages but no response packet is returned. The Modbus master issues a command to start the transaction. The command contains a unit address specifying the slave to respond. The slave processes the command and returns a single response. Message integrity is assured through use of checksums included in the messages. The slave ignores all messages that have invalid checksums and assumes the master has received any responses sent. It is the Master node s responsibility to provide time-out and retry provisions. Before the HE150RTU100 responds appropriately to Modbus commands, it must be configured to the frame protocol used on the bus. This includes items such the media (RS-485, RS-232 or Modem), frame protocol such as (ASCII or RTU), baud rate, parity and stop bits, and finally optional handshaking. 3.2 Port Selection Either RS-232 or RS-485 may be used for communications through the software configuration. The LED s on the front panel monitor activity on these ports. See Figure 1.1. Table 3.1 Port 1, RS-232 Pin # Signal Name Direction 1 (DCD) Always High Output 2 (TXD) Transmit Data Output 3 (RXD) Receive Data Input 4 No Connection N/A 5 (GND) Signal Ground N/A 6 (DSR) Always High Output 7 (CTS) Clear To Send Input 8 (RTS) Request To Send Output 9 (RI) Always High Output Table 3.2 Port 2, RS-485 Pin # Signal Name Direction 1 Not Used 2 Not Used 3 Not Used 4 Not Used 5 (PWR) 5 VDC Power N/A 6 (RTS-) Request To Send Output 7 (GND) Signal and Power Ground N/A 8 (CTS+) Clear To Send Input 9 (TERM) Termination Input 10 (RXD-) Receive Data Input 11 (RXD+) Receive Data Input 12 (TXD-) Transmit Data Output 13 (TXD+) Transmit Data Output 14 (RTS+) Request To Send Output 15 (CTS-)Clear To Send Input

11 PAGE 11 5-Nov-1998 CHAPTER 3: OPERATION 3.3 Frame Protocol RTU mode sends each byte of information in binary form thus requiring 8-bits of transmitted data. ASCII mode divides a byte of information into two nibbles (of 4-bits each) and then transmits each nibble as a 7- bit hexadecimal character. Therefore, ASCII mode uses twice as many transmitted characters; however, debugging with printable ASCII characters can be much easier. Therefore, setting the mode to either ASCII or RTU indirectly sets whether the data size to 7 or 8 bits. In addition to the mode, the baud rate, parity and the number of stop bits must be set to that used the bus. All these parameters are changeable with software configuration. Note: The following frame protocol combinations are NOT valid for the HE150RTU100 and should NOT be used as the bus frame protocol. ASCII mode, 1 Stop Bits and No Parity. This combination requires 2 stop bits before the HE150RTU100 accepts any characters and thus is invalid. RTU mode, 2 Stop Bits and either Even or Odd Parity. This combination generates only 1 stop bit, which may or may not, effect the application s reception of characters and thus is invalid 3.4 Handshaking The HE150RTU100 provides five (5) different handshaking modes to provide for multi-drop configurations or to limit data flow back to masters with hardware/software limitations. Table Handshaking Handshaking No Software Hardware Multi-drop Radio Modem Description No hardware handshaking is provided. If the slave returns data at a rate and value the master is unable to handle, data is lost. If the RS-485 is used, the transmit driver is enabled continuously. The HE150RTU100 module suspends sending data on the reception of a XOFF character. Transfer continues on the reception of a XON character. Note: This mode should not be used with RTU mode. The HE150RTU100 asserts CTS continuously to sender. RTS is monitored during HE150RTU100 transmissions. If the master drops the RTS line low, the HE150RTU100 suspends the transfer. Transfer continues when the master raises the RTS line. Multi-drop handshaking is required for RS-485 multiple node (either single or halfduplex) or single node half-duplex configurations. The transmit driver is only enabled when the HE150RTU100 is transmitting. For RS-232, this mode controls the CTS signal for compatibility with RS232-to-RS485 converters that are operated in a half-duplex mode. Note: When multi-drop handshaking is enabled, no other handshaking is available. This mode is similar to hardware handshaking with the exception that CTS is only asserted when the HE150RTU100 has data to send. Thereafter, the HE150RTU100 sends or suspends data transfer based on the RTS line. The radio modem mode also provides an optional modem turn-around-timer (TAT). If the modem does not respond to the CTS line within a specified period, the transmit buffer is flushed; CTS is dropped and the frame is lost. See section 2.3 to set the modem TAT.

12 PAGE 12 5-Nov-1998 CHAPTER 3: OPERATION 3.5 DCS Active Detection The HE150RTU100 provides the capability to optionally monitor the activity from the Modbus master. Should that activity drop-off, a bit is set in both the DCS Status Bit (as specified in WL0004) and the Modbus exception status byte; furthermore, the DCS LED begins to flash at a 1 second intervals. This provides a method for the CPU, maintenance operator to determine if the master is functioning properly. The DCS Status Bit and the DCS LED is reset immediately when communications with the master is restored. The bit in the Exception status byte remains set until after the Modbus Read Exception command is received. To enable this feature, set the DCS Time-out (WL0003) with the amount of time the HE150RTU100 waits after the last communication with the master before setting the DCS Status Bit and flashing the DCS LED. Time-out value must be between 1 to 320 seconds. Setting DCS Time-out to 0 disables this feature. Note: When setting DCS Time-out, the DCS Status Bit (WL0004) must also be set. If specified L register in WL0004 is invalid (i.e., above 3FFF or in the CPU write area between TOP and END, the DCS Time-out function is disabled. 3.7 Front Panel Diagnostic LED s Referring to Figure 1.1, RXA and TXA flicker when there is activity on the RS-232 port. Similarly, RXB and TXB flicker when there is activity on the RS-485 port. On power-up or if the valid configuration parameter ID is not set, the DCS light is solidly lit. Once the configuration is properly set the DCS light goes out. Thereafter, if the DCS timer has not timed out or is not enabled, the DCS LED momentarily lights when a valid Modbus message has been received and is being processed HE150RTU100. If RX light is flashing and the DCS is not, this generally indicates that the frame protocol is incorrect. If DCS is enabled and timed out, this LED flashes every 1-second. 3.9 Supported Modbus Commands The following Modbus commands are supported: Table 3.4 Supported Modbus Commands Code Meaning I/O Unit Min Max Duplicates 01 Read Coil Status I Bit Read Input Status I Bit [01]* 03 Read Holding Registers I Word Read Input Registers I Word [03]* 05 Force single coil O Bit Preset Single Register O Word Read Exception Status I Bit Loopback Diagnostic Test Force Multiple Coils O Bit Preset Multiple Registers O Word * Indicates that this command duplicates that function code listed. The reference accessed is instead determined by the specified reference (Address).

13 PAGE 13 5-Nov-1998 CHAPTER 3: OPERATION Modbus command descriptions It is not in the scope of this document to describe each command in detail. For more specific information on the standard Function Codes, Sub-function Codes and exception responses, refer to the Gould Modbus Protocol Reference Guide (PI-MBUS-300 Rev. B) published by Gould Inc. HE150RTU100 specific information is described below for the Read Exception Status and the Loopback Diagnostic Test Read Exception Status command (HE150RTU100 specifics) The Modbus Read Exception Status command returns a byte value that indicates the status of the HE150RTU100. The following defines each bit in the status byte. Bit MTE MRS n/a n/a n/a n/a n/a n/a DCS Time-out has occurred; cleared after Read Exception Status command. CPU/HE150RTU100 has been reset since last Read Exception Status command Loopback Diagnostics Test command (HE150RTU100 specifics) The HE150RTU100 supports the following standard Diagnostic Codes for the Loopback Diagnostics Test command: Table 3.5 Supported Loopback Diagnostic Test Commands Code Meaning 00 Return 2-byte Data Field (loopback test) 01* Reset HE150RTU100 02* Return 16-bit HE150RTU100 diagnostic register (always zero) 04 Force Slave into listen only mode 10 Clear counters and diagnostics register 11 Return 16-bit bus message count 12 Return 16-bit bus invalid error check count 13 Return 16-bit Slave message count 14 Return 16-bit Slave no response count *HE150RTU100 specific Diagnostic Codes [01 and 02]: 3.10 Modbus Responses Modbus commands and responses consist of message frames that contain the following information: a. Slave Address b. Function Code c. Data d. Error Check Code If the address in a Modbus command matches a slave address and the received data is validated by the slave with the Error Check Code, then that slave executes the indicated function. The slave then issues a response based on that function. Alternately, if an address of 0 (broadcast) in the Modbus command, all Modbus slaves execute the command; however, in this case no slave issues a response. Note that only

14 PAGE 14 5-Nov-1998 CHAPTER 3: OPERATION Function Codes of 5, 6,15,16, 72 and some sub-functions of Function 8 may be broadcast. A normal response contains the same slave address and function code as the request; however, the individual data field(s) may vary according to the function. If the Modbus slave detects an error either internally or in the command parameters, the command is not executed and an Exception Response is returned. An exception response is indicated by setting the high bit in the returned function code and returned data byte describing the exception. The HE150RTU100 supports the standard Exception codes listed below: Table 3.6 Exception Codes Code Name Description 01 Illegal function Invalid command function was sent 02 Illegal data address Invalid reference, or size exceeded table bounds 03 Illegal data value Not valid data for a particular reference 04 Failure in device Valid configuration identifier <> A5A5H

15 PAGE 15 5-Nov-1998 CHAPTER 4: WIRING CHAPTER 4: WIRING 4.1 RS-232 Connections RS-232 Port 9-pin D-sub TD RD RTS CTS External Modem 25-pin D-sub RD TD CTS RTS 0V 5 7 0V Figure 4.1 RS-232 to Telephone Modem HE693RTM705 Modbus Master Port 1 25-pin D-sub TD RD RTS CTS RS-232 Port 9-pin D-sub RD TD CTS RTS 0V 7 5 0V HE693RTM705 Modbus Master Port 2 25-pin D-sub TD RD RTS CTS RS-232 Port 9-pin D-sub RD TD CTS RTS 0V 7 5 0V Figure 4.2 HE150ETN150 to HE693RTM705 Modbus Master (Port 1)

16 PAGE 16 5-Nov-1998 CHAPTER 4: WIRING 4.2 RS-485 Connections HE693RTM705 Modbus Master Port 2 25-pin D-sub RT RD(B ) RD(A ) SD(B) SD(A) RTS(B) RTS(A) CTS(B ) CTS(A ) 0V RS-485 Port 15-pin D-sub RD TXD+ TXD- RXD+ RXD- CTS+ CTS- RTS+ RTS- 0V RS-485 Port 15-pin D-sub 9 RD 13 TXD+ 12 TXD- 11 RXD+ 10 RXD- 8 CTS+ 15 CTS- 14 RTS+ 6 RTS- 5 0V Figure 4.2 HE150ETN150 to HE693RTM705 Modbus Master (Port 1)